In inverted vehicles such as inverted two-wheeled vehicles, it is one of the important matters to be able to enable a rider to safely get off the vehicle even when an abnormality occurs in the system. An inverted vehicle performs inversion control based on an output(s) from a sensor(s). Therefore, it is very important to detect a failure in a sensor and a failed sensor with high accuracy and to prevent inversion control based on the output from the failed sensor in order to secure the safety.
Patent literature 1 discloses a vehicle in which a power base in which a power supply, a sensor electronics board, and a control processor are integrated as one combination unit is constructed with triple redundancy. This vehicle detects a failure in a sensor by comparing data supplied from triple-redundancy sensors with each other.
However, when a plurality of sensors each having the same configuration are simply constructed in a redundant manner as in the case of the vehicle disclosed in Patent literature 1, there is a problem that the cost increases. For example, assume a case where a gyro-sensor is installed for each of three orthogonal axes in order to detect an angular speed around each of the three orthogonal axes in the sensor electronics board. In such a case, since the sensor electronics board is constructed with triple redundancy, nine (3×3) gyro-sensors are necessary in total. That is, there is a problem that the cost increases. Incidentally, Patent literature 2 discloses an inertia reference apparatus that calculates angular speeds around three orthogonal axes from angular speeds measured by four gyroscopes that are obliquely disposed with respect to each other.